Schluter Shower install - wicking issue

I could use insight into if there is an issue and how to solve it. After much research, I decided to use the Schluter shower kit. I followed all instructions, used Dietra Set unmodified thinset to install it all. I followed the install process in the manual, putting the kerdi band around the corners, then covering the walls. underneath is concrete board.

after 30 hours of drying, I went to water test it and did a short test spraying water into the shower. I could see water wicking into the kerdi on the floor seams. Schluter rep I called said that an inch is normal but I was seeing 3.5 inches in the worst spot and that wasn't normal.

I'm awaiting a visit from the field rep who will look at it to see whta went wrong, but that will take 2-3 weeks. ugh..

anyone experience this issue with Schluter kerdi before and what might be the problem?

is there a good way to solve this? I've never used Redguard, but I wonder if putting that over the seams would be an easy fix?

I have deleted all my posts showcasing Kerdi, Ditra and the like from Schluter Systems. I have stopped using these products and do not recommend them now to my online clients, my local customers. You will not see photos here going forward. No one asked me to delete these photos. No one told me to delete them. I feel these products from Schluter come with far to many restrictions and that the testing of the products leaves lots to be desired.

It was my testing of the niches and resulting phone call to review my findings that finalized my decision to switch to a more premium waterproofing approach a quit using Schluter's products all together...

If you need help with a Kerdi Question email Dale at DKempster@schluter.com - this is Schluter's top tech. Remember that Jadnashua (Jim) here on Terry's forum is not in this business and by my account works to privately promote Schluter and the John Bridge Tile Forum.

One thing that makes a big difference is if you don't wipe down the walls with a wet sponge first, you will find it very hard to get the membrane embedded properly. The wall WILL suck out too much moisture, making the membrane very difficult to embed.

Second thing, did you pull a section back off the wall to test that you were getting it well embedded? This is very important, especially if it's the first time you have done it, and even after you have some experience.

Third, if you try to put up too big of a piece at one time, you may get part of it attached well, but the rest, the thinset may have skinned over. Same idea with wiping the wall down before ready to spread the thinset and add the membrane. Some areas are already into the heating season, so hot, dry air can dry things out fast.

Fourth, if the thinset is too stiff (too dry) or not stiff enough (you added too much water), in one case, it's really tough to get it to embed, and the other, there may not be enough to provide a strong bond.

Fifth, does the color look the same all over, or is it blotchy? Can you see the trowel ridges? Once you've embedded it well, the color changes a bit - if you don't use something like either a grout float or the straight edge of the trowel and push some, you will not get it embedded properly. There's a sweet spot between too much and too little, but it's fairly broad. The clincher, though is to pull it back off and look at the coverage - you should have full coverage on the back of both the membrane and the wall.

You don't have to use their trowel, but you should use one that provides the same amount of thinset. Too small of a notch, and you can't embed things properly. To thick, and it can wick. They told us in class, it's the fibers between the two sheets interacting that disrupt the capillary action. If there's too much thinset, you'll have that thinset layer outside of the fleece, a much bigger buildup and that will make it more difficult to keep a nice flat surface for tiling.

It's not really too hard if you use a trowel the right size. But, it does take some skill. It's easier if you've seen it done, but the biggest test is to pull a section back off and check the coverage. That will give you an understanding if you've been doing it well so you can adjust your technique.

I think it's actually a little easier to put up the banding at the seams, then add the big sheets, but it works either way if you get things embedded properly.

Did you eyeball the mixing of the thinset, or did you measure and weigh the materials? Most DIY'ers can't mix a full bag and use it before it goes off (starts to set), so it's important to measure. I tend to use a fairly accurate bathroom scale (reads to 0.1 pound) and a measuring cup. Adjust slightly if required, but you should never use more than the max liquid/powder as shown on the bag.

If the thinset had started to go off before you finished, and tried to use it to finish up installing the Kerdi, that could produce a poor bond and fail to embed the fleece.

How long did you wait before you flood tested? Last I looked, the instructions said 24-hours. If you did it too soon, that just by itself may be the reason things wicked. You might have had everything wonderful, but rushed it.

A picture or two might help, but that's the sort of thing that is much easier to evaluate in person. Hopefully, the rep will be able to get there in short order...but, some of their regions are fairly large.

I will ping them on facebook and twitter and email you. the Rep I called indicated he was traveling next two weeks, but I'll apply pressure, I don't really want to be cutting tile in middle of December.

to answer the questions, that may help uncover if I did something wrong and where...
When I leveled the floor, the leveler bag (RS stuff from orange box store) specified lb of material to quarts of water, so I weighted that on my mailing scale to the oz and measured fluid. But when I read the ditraset instructions, I don't recall seeing any measurement, maybe I missed that? I thought they said mix it to a consistency"mix to a flairly fluid consistency but still able to hold a notch". so I added water and added material and mixed til I got a consistency and let it slake 15 min and remixed then applied it immediately. It is possible some of it sat too long when I did the walls as that took a long time to apply, but I mixed it in batches of about 1/3 or 1/4. the floor piece which is what is leaching, was mixed fresh.

Possible I mixed it too dry.. definitely was not too wet, It seemed workable at least 1/2 hr...

When I applied it, I used the notched trowel size they recommended. The parts over the durarock, I wetted the durarock and the back of the kerdi a little, although that was hard to wet. I pressed the material into the durarock and notched over it. It is possible I applied it too thick and held the trowel at too much angle. then I went over it with the flat side of the trowel and pushed the kerdi in to get the bubbles out per watching the videos. I wonder if I worked it too much and pushed out too much thinset? I got a lot of thinset out. In the video it looked like they were pressing and worked it in, so that's what I did.

I pulled back a few sections especially on the edges and looked ok like was coverd, but didn't do that on the floor piece. pushing the material into the thinset I figured would resolve any issues around that and if no bubbles...good??

it is hard to see in the photo but the leaching at its worst was 3.5" in. other areas maybe to 1.5 or 2. again, I called Schluter and they indicated some leaching was normal and that's why they have a 2" min overlap, but mine was excessive. the tech rep indicated he hadn't heard of this before....makes me wonder about this product and how difficult it really is to install.

color looked the same all over when installed other than the leaching area after water test.

the part that is wicking is around the edge ontop of the kerdi band and ontop of the foam base. I also see it wicking around the drain and the kerdi (wicking in). One would think the kerdi would stick well to the kerdi band on their stuff. I didn't see a problem on the walls where the durarock is, but didn't test very long there. this was a brief several minute test with a drain plug that didn't work.

I will try the shop vac test. any size shop vac with no attachment? I have the Rigid big vac, just not sure if any amount of pressure should pull it away.

Also, suggestions on plugging the drainhole completely on this test? I hadn't figured that out yet.

I'm glad to hear there is a way to seal those seams. if I pass the shop vac (e.g. the stuff is attached to the walls good enough that the tile won't pull it away, then I'll give a little time for the rept to look at it and at least have a way to seal the seams. Thanks for the picts as it helps to see there is a decent solution. I went looking for the Ardex 8+9 and couldn't find it at big boxes or local hardware. I'll call the rep, probably only specialty tile shops have it.

on another note, I have to say I was quite "challenged" trying to find a thinset for this job. Schluter says modified premium, well that can't be found at most places including the orange big box store I bought the shower kit. after reading many reviews, I looked at laticrete 317 and Ditraset. Since I wantd to put up porcelain tiles with unmodified per the Schluter instructions, I used Ditraset.

I am a new DIY to the forum. I haven't done a shower project before and been 10 yrs since I did tile. I'm not following the doubt statement. here's a few other picts I have of before. I'm out of town so can't get a better picture of the wicking.

note the base is poured self leverler over plywood prior to installing the kerdi tray.

I don't understand the doubt on the forum that I'm real DIY, but I haven't done much posting other than a post on the John Bridge about deflection in my joists, I can add color on that if you like. I guess noone knows online who is a product rep, vs someone trying to bias to/from products, or sites, etc.. so it is a social networking soap opera?? anyway, I'm the real deal. 47, 5'6, 155lb work full time as a Product Manager in fin svcs and fixing my house full time DIY. I hire sometimes when I know I'm over my head or dont' have time. I actually like doing this stuff though, learning, and doing, its kinda therapuetic? but it's starting to get to be a bit much on this project given all the headaches of process, finding materials, design, and doing the work, etc.. . As a Product Manager, I can say for sure I do not like what I see going on with products...e.g. I can buy the Schluter shower kit at orange box store but they put "custom blend" thinset near it that is not premium and thus not what they recommend to install it. definitely some product games going on that are not friendly to the consumer. Add to that it appears this is more challenging than read the instructions.

I read john bridge forum and this one prior to buying the 48x48 shower kit. I was concerned about pouring my own base so went with the shower kit in the thought it would make it easier. That was the rational, not saying it was good rational. it would have been really easy to mess up the foam base since my shower wasn't all square and had to cut it down, but I think I got that right.

anyway...
I've been talking with lady at Schluter today for a while on this. Not sure about their product yet, but their support via phone is very good. get someone quick, speak clearly, they are friendly, and helpful. the issue with the local rep is he is traveling and I accept people go on vacation/confernces. but I don't want to wait 2-3 weeks to have someone look at it to tell me I have to either redo it or do something that will take more days...then I'm cutting tile in freezing cold. So I got the name of another rep and will call him today. I would think that the $4xx cost of the kit, the materials are small part of the cost and the support is a lot of it. Lets hope...

comments from the Schluter phone support:
* they noted they don't hear of showers failing the water test that often. makes me wonder if people are really water testing or if something just went wrong here...
* do another test and see if the added water may have helped it cure more and resolve, or see if anything has lifted and pulled away. (I'm OOTown so will check it sunday).
* did not recommend the vaccum test. she indicated it can tear away from the edges even if adhered correctly and then have to cut that away and put 2" kerdi band over it. I find that odd it couldn't withstand that much pull but could hold a tile, but I'll defer doing anyything until I have someone come out.
* She of course couldn't recommend the Ardex but did suggest the kerdi fix as possible solution. I talked to Ardex/Henry and they affirmed it can be used to seal the Schluter. I can't find Kerdi fix anywhere so far and am hunting for the Ardex.

I'm going to talk to the other area manager, see when I can get him out there or get a judgement and make decusuib from that on what to do next.

will keep you posted on the continuing saga so others know how this all goes.

I didn't notice if you said you washed the walls down first before installing the thinset. This is a crucial step, especially on cbu. Even if your thinset is mixed properly, it can make for a bad bond. CBU is REALLY thirsty, and can dry the thinset out way too fast...dried thinset doesn't bond well, cement needs moisture to hydrate and cure. Cement grows interlocking crystals when it has enough moisture to cure, and this is what makes the bond...not enough moisture, poor bond.

All membranes must pass a bonding test and the number is 50psi, and tests show 75psi is typical on Kerdi and Ditra AFTER it has fully cured (industry standards are after 28-days for ANY mortar, this is not specific to Kerdi or Schluter). There's more than enough strength to start to lay tile on Ditra immediately after embedding it, and Kerdi as well. For maybe as long as a week, if you catch an edge, and try to peel it back, it will come off, usually tearing a bunch of the fleece off in the process, but it will come off. So, catching an edge with a vacuum, depending on how you caught it and how you moved it, how long it has been on the wall, and, obviously, the strength of the vacuum, you could damage the install further.

In the example John showed of a poorly installed shower, it was obvious that they did not get good bond on the membrane. That is why it is critical to peel back the sheet to check occasionally to verify both the surface and the membrane are fully covered...you should not be able to see any of the membrane, and the wall should be covered with thinset, if it is done properly.

Most of the time, when you embed the membrane, it ends up a bit sloppier on the surface because you run from the middle to the edge, and this pushes any extra thinset out of the seam. Your seams are pretty, but you may not have embedded things well, and may have excess thinset there. For certain, you don't want lumps, but neatness isn't particularly critical here...getting the membrane bonded well is, and that tends to be not what I see.

Only way to be certain is to have someone look at it that knows and understands it well. It's hard to do from pictures.

I did wash walls with sponge with water, about twice. but the juncture issue is at the foam tray, covered with kerdi band, covered with kerdi, right at where the kerdi meets kerdi band.

I did embed by pushing the thinset in with a flat 6 to 8" blade (what would use to apply drywall compound). Schluter rep thought that was right. I got a lot of thinset out the side and worked out bubbles. it wasn't too messy on the edge, but there was some. it wasn't real wet though or mushy. I could pick it up and put it back in the bucket.

of everything I've heard, the theory that the thinset wasn't wet enough and the heat kicking on dried it up too fast makes most sense. if I saw thinset mixed up correctly, I may be able to tell. I'll have to look for videos on that.

http://www.bostik-us.com/sites/default/files/Ditra-Set.pdf 5-6 quarts to a full bag. When mixed in the right proportions, it's about the consistency of mayonnaise. For embedding the fleece of Ditra or Kerdi, you'd probably want to go towards the top of that allowance. That works out to a little over 38oz water to 10# of dry thinset. Because Ditraset also qualifies as a medium bed mortar, if you needed that extra depth, you'd probably mix it towards the lower end of that allowance, IOW, closer to 5qt/bag verses 6 when embedding it in the fleece.